In medical terms, a stent is a man-made “tube” inserted into a natural passage or conduit in the body to prevent, or counteract, a disease-induced, localized flow constriction. The term may also refer to a tube used to temporarily hold such a natural conduit open to allow access for surgery. Stents include vascular and non-vascular stents. Vascular stents are designed for applications in the vascular system, such as arteries and veins. Non-vascular stents are used in other body lumens such as biliary, colorectal, esophageal, ureteral and urethral tract, and upper airway
Stents are available in permanent and temporary varieties. Stent duration is heavily influenced by the construction material. For example, metal stents typically have a much longer use life than plastic stents. The stent body typically has a central lumen that allows blood or other body fluid to flow through the stent. A common problem with the current stents is that they routinely migrate and clog, thus requiring additional procedures for extraction and/or replacement. There exists a need for improved stents that are easy to make and safe to use.